How good to keep SRVCC “Off” and CSFB “On” or vice-versa in VoLTE enabled network?

Hello All.

How good to keep SRVCC “Off” and CSFB “On” or vice-versa in VoLTE enabled network?

The best setting for you depends on your specific needs and the coverage in your area. Here’s a breakdown of the advantages and disadvantages of each setting:

SRVCC “Off”, CSFB “On”:


  • Better call quality: VoLTE calls generally offer superior sound quality compared to CSFB calls. By keeping SRVCC off, you prioritize remaining on VoLTE for as long as possible.

  • Faster call setup: VoLTE calls connect faster than CSFB calls.

  • Lower battery consumption: VoLTE is more efficient than CSFB, so keeping it active can save battery life.


  • Dropped calls: If you leave an area with VoLTE coverage without CSFB enabled, your call will drop instead of seamlessly shifting to 2G/3G networks.

  • Limited coverage: You might be able to make data calls in non-VoLTE areas even with SRVCC off, but voice calls will only work if you have 2G/3G coverage.

SRVCC “On”, CSFB “Off”:


  • Seamless call handovers: With SRVCC, your call will automatically switch to 2G/3G networks without interruption if you move out of a VoLTE area.

  • Wider coverage: You can make and receive calls even in areas without VoLTE coverage as long as there’s 2G/3G signal.


  • Potential call quality drop: Switching from VoLTE to 2G/3G might affect call quality, especially in areas with weak signal strength.

  • Slightly slower call setup: SRVCC handovers add a small delay to call setup compared to direct VoLTE calls.

  • Higher battery consumption: The network switch during SRVCC handovers can temporarily increase battery usage.

Ultimately, the best setting is the one that works best for your needs and preferences.